This invention relates to washing machines having impellers to be rotated unidirectionally, and particularly to washing machines with gyrators having spiral driving surfaces on the bases and the posts thereof to be rotated at speeds commonly used for spinning.
A brief history of the background of development of unidirectional washing machines is given in the background of U.S. Pat. No. 4,103,522 issued to the present inventor on Aug. 1, 1978. The gyrator described in that patent has a low profile with a volute surface that drives the wash outwardly along the bottom of a tub. Because of the gradual outer, spiral surface of the gyrator, it can be rotated unidirectionally with minimal whirling and entangling of wash. Earlier washing machines having gyrators to be rotated unidirectionally did not wash as well as reciprocating impellers, and special precautions had to be taken to prevent whirling and entangling.